The present invention relates generally to concrete products, and more particularly, to a method of producing simulated quarried stone by utilizing surface-seeded exposed aggregate concrete.
As is well known in the building and construction trade, concrete is extensively utilized as a building material for industrial, commercial and residential applications. Due to its durability, water resistance, and cost economy, concrete has gained wide spread use in flooring applications. With this wide spread use, the public is currently demanding variations in color, surface texture and overall appearance of concrete so that the concrete possesses improved aesthetics similar to more conventional and costly flooring surfaces such as marble, stone and granite.
In order to meet this demand, the concrete trade has developed various coloring and surface finishing techniques to enhance the aesthetics of concrete. Examples of such finishing techniques include salt finish, multiple broom finish, form press finish (e.g. stamped concrete), and exposed aggregate finish.
With particular regard to exposed aggregate finishes, one of two different production methods or techniques are typically utilized to form the same. The first is the “integrally exposed aggregate” method, which is the more conventional of the two techniques. The integrally exposed aggregate method entails washing or removing surface cement and fines from the concrete while the concrete surface is still plastic (i.e., prior to full curing) such that the aggregate (which is normally rock or gravel) is left exposed on the surface of the concrete. Due to the fact that the concrete aggregate is relatively large in size (i.e., approximately one-half inch to one inch in mean diameter), as well as the fact that the washing process is not uniform in nature, the resultant concrete surface produced via the integrally exposed aggregate method is often extremely rough and jagged. This characteristic limits wide spread use of the integrally exposed aggregate method in flooring applications. Further, the rough and jagged appearance also fails to create the aesthetic appearance of stone or marble that is desired.
The second method is the “surface seeded exposed” method, which has recently been introduced into the trade. In this particular method, subsequent to pouring the concrete, rock or gravel aggregate is scattered (i.e. broadcasted or seeded) over the top surface of the concrete and subsequently troweled into the same. As the concrete cures, the aggregate becomes adhered to the top surface of the concrete and is thus exposed. Although various sizes of aggregate can be broadcast over the top surface of the concrete in this method, such aggregate is normally of about three-eighths inch diameter or greater in size, and has sheared or jagged edges. The size and shape of the aggregate allows it to be worked into the top surface of the concrete and adequately adhered thereto. However, although the resultant concrete surface produced through the surface seeded exposed aggregate method is flatter than the surface produced through. the integrally exposed aggregate method, neither surface is free of irregularities, and both surfaces still posses an extremely rough surface finishes which limit their wide spread use in flooring applications. In particular, neither method produces a surface finish comparable to that of marble, stone, or granite.
In order to overcome the above-mentioned deficiencies of the prior art, methods have been developed to enhance the surface finish of concrete by reducing the size of the aggregate exposed on the surface of the concrete. However, as the aggregate decreases in size, other challenges develop due to the alkali-silica reaction (ASR). ASR is a chemical process through which alkalis from cement and silica from aggregate, combine to form a gel that expands in the presence of moisture and causes cracking in concrete and disrupts the adhesion of aggregate to the top surface of the concrete.
In response to the challenges that ASR presents, other methods have been developed to obtain sufficient surface flatness while substantially eliminating the effects of ASR. In particular, several of these methods are described in Applicant's U.S. Pat. Nos. 4,748,788, 6,016,635, and 6,033,146, the contents of which are incorporated herein by reference. Applicant's techniques as described in the above-mentioned patents overcame many of the deficiencies of the prior art and produced improved surface finishes on surface seeded exposed aggregate concrete. In particular, the concrete resultant from practice of the above-mentioned patents exhibits an extremely flat exposed aggregate surface suitable for extremely high traffic flooring applications. However, although the surface seeded exposed aggregate method has hitherto been refined to produce surfaces that assimilate more costly surfaces such as stone, marble, or granite, no process has been developed to model the fine, medium, and coarse grain textures of natural quarried stone.
Therefore, there is a need in the art for a surface seeded exposed aggregate method that produces surfaces which model the fine, medium, and coarse grain textures of natural quarried stone. Further, there is a need in the art for a surface seeded exposed aggregate method that incorporates flecks, speckles, and inclusions of natural quarried stone.